Process for producing perforated sheet sponge rubber



.May 25, 192e.

, C. T. DICKEY PROCESS FOR PRODUCING PERFORATED SHEET SPONGE RUBBER Filed April-4, 1925 fi" i www@ ATroRNEY ritmica' May 25,1926.

UNITED STATES PAT-ENT OFFICE.

. CHARLES T. DICKEY, OF ELZABETH, NEW JERSEY.

Paocnss ron Paonucine' rnnroaarnn snaar sroNen numana.

Application med April 4, 1925. Seriar No. 20,768.

My invention relates to a new, novel and useful form of sponge rubber and processi for producing the same and: refers particularly to sponge rubber in perforated sheet form. i.

Because of the lightness, heat transmission properties .and other valuable attributes possessed by sponge 'rubber and which are not incidentto solid rubber, spon e rubber has applications to which solid-ru ber can? not be so advanta eously employed.

This is especial y true when the sponge rubber is inisheet formiv4 Inthe employnzienty of ysponge rubber, it

is frequently, desirable that the sheet should `have openings therethrough frpurposesof ventilation, or in order4 that airro'r liquids may pass therethrough, and as examples of such use,.mention"may be madaof bandages and corsets. j {if} I: It is evident that if the interstices, or cells,

of s onge rubberbe exposed tofinoisture,-- or liquids, thatthe liquid will accumulate within the interstices, or cells, and that suoli f-.an accumulation is highly undesirable,and 1njuriouaiivhilthis actionA results where the sponge 'rubber sheet is maintained in* close contact withthe human body: thereby producin the' exudationand accumulation of" perspirati'oniV ThisA accunui'lation' of perspi ration within thexsponge rubber cells-niain-.ll

tains thebody in ai moist condition, preventing the proper' fun cti0ning of. the skin cells, and resulting 'atitiin'es in serious irritations. It is levident,therefor-e, that the proper and desirable'. eiciency of sponge rubber sheets for the purposes mentioned, and other similar uses, 1s dependent upon the' nonabsorbent properties `of lthe-rubber.A i

The present employed `method. for pro- .,l ducing perforated sponge rubbersheets isv to punch out, or cut out, a; plurality'of -por- -spon e`;rubber.`l f

that wh'enholes are formed tions of the sheet, thus producing `a plu'- rality of openings therethrough.- The sheets.

employed for this l covered upon bothy aces witha4 thm layer of non-porous, non-absorbent] rubber, be-

urpose are 'frequently which all of .the'rubber afterperforation. y

through, and that the acid, disagreeably.

odorous erspiration, in the ,uses mentioned, wil be retained, and that'the movement of the rubber sheet incident to its use will cause this perspiration` to maintain the skin in a moist condition and cause an irritationy thereof.

It isevident, therefore, that a proper perf'orated sponge'rubber sheet should be of such a character 'and construction that n'ot only should the-'twoV face surfaces be im.

ei'vious to moisture, but that it is lof equal importance that'the .walls of the Vperforav tions be also impervious tol liquids. l

The process of my y invention overcomes the above mentioned .undesirable pro orties i" and' resents a Ameans whereby the entire expose surface of; perforatedsheet vsponge rubber is ma ey imperviousto. watergand in "l5 e .interstices or, cells, of the rubber are covered'with a` sheet of noiif walls of the perforations.,', i

` In the-accompanying drawings illustrating the ap lication of my process, similar vparts Aarc esignated by similar numerals.

Figure 1 is a vertical cross-section show- `ing the i plosi'tions of the various elements e`= formation ofthe perforation.

priorv to t Figure. 2. is a cross-sectional view Figure-3 is a cross-section otheaperforl I ated mold. 4

Figure 4 is an' enlarged cross-sectional 4pervioua rubber, including those within thei showing ,View of the rubber within the moldsl preparatory to vulcanizing. 4

Figure 5 is thesame vi after vulcaniza-tion and sponge formation. y Figure' 6Y yisa top plan view of the nished .perforated sponge'rubber sheet. Figure 7 is a cross-section 'through the line 7-'- 7 of Figure l6.

l he process of my invention isf-clearly shown when described-in connection with the accompanying drawings. l

A hydraulic plunger 10 carries a'sheet 'of soft rubber 11. The corresponding hydraulic plunger 12 carries a removable late 13 having a plurality of extended meta lic per-'4 forting pins 14.14,' a portion of each pin being cylindrical as shown. The sheet of unvulcanized rubberY to be treated and perforated 15 is placed u pon the soft rubber sheetll, the unvulcanized rubber being of ew as Figure 4., but i I any suitable composition for the production of sponge vr-ubber during vulcanization..

The two hydraulic plungers 10 and 12 are then moved toward each other, 'the pins- 14.14, passing through the 'rubber sheet 15 and into the soft rubber sheet 11, the latter being employed to back up the rubber sheet during the perforation process.

The plungers 10 and 12 are then moved apart and the plate 13 and rubber sheet 15 removed from the plunger 12. The rubber sheet 15 then has the general appearance shown in Figure 2. v

The perforated mold element 16 having the perforations 17.17, exactly corresponding to the pins 14.14, is then placed over the pins 14.14 as shown in Figure 4, and the plate 13 'and the mold element 16 are attached to 'each other by any convenient vmeans. l

This mold with the 'contained rubber is then heated and vulcanized, resulting in an expansion of the rubber sheet 15 and the formation of sponge rubber 1 8. It is to be noted that during this process thel rubber has expanded to completely fill the chamber 21, and that the pressure of this rubber lmass against the ht metal of the plate 13,`the

pins 14.14, and the plate 16 forms a coating,

or layer of solid rubber 19 over the entire rubber sheet including the side Walls. of the perforations 20.`v`

The accompanying drawings are diagrammatic and are simply illustrative ofthe sev# eral steps of my process.

From the above, it will be seen that by my process j I produce' a sheet of perforated sponge'rubben the outer faces of which are covered by a layer of solid, non-sponge rubber, thuscompletely closing and "covering all of therubber cells and interstices from contact with the outside atmosphere.

I do not limit myself to the particular ap paratus, steps of process, orL method of proced'ure sliofvvn and described1 as these are given"simply 1as a means fr clearly describmy invention.v i hat I claim is :--'-l 1. In the process of producing perforated sheet lsponge rubber having V'its entire sur- 'ser' face `:covered `with solid rubber,theV steps which comprise; passing perforating means through ahsheet `OfunVulcanized rubber,

` maintaining said perforating means within the rubber sheet during vulcanlzation and vulcanizlng the unvulcamzed rubber sheet.

2. .In the process of producing perforated sheet spon e rubber having its entire surface covered Wlth solid rubber, the steps which i comprise placing a sheet of' unvulcanized 'rubber upon a sheetlof soft rubber, forcing a plurality of perforatng means through the unvulcanized rubber, maintaining said perforating means Within the unvu lcauized rubber sheet during vulcanization and vulcaniz ing the unvulcanized rubber sheet.

3. In the process of producing perforated sheet sponge rubber having its entire surface covered with solid rubber, which comprises 'passing perforating elements through a sheet of unvulcanized rubber, forming a mold for the perforated rubber having an interior capacity. greater than the rubber, and vulcanizin and sponging the rubber within the mol While the perforating elements are within the crforations.

4.` In the process ofp' producing perforated sheet sponge rubber having its entire surface covered with solid rubber, which comprises passing perforating elements through a sheet 4of unvulcanized rubber, and vulcan izing the perforated rubber Within a mold u'hilew'the perforating elements are within the perforation's, whereby-a sheet'of sponge rubber having solidrbber overnits entirety '5. YIn thel process -of producing perforated sheet sponge rubber hav'rig'its entire surface covered with solid rubber, the-step ivhich.

comprises forcing a plurality offperforating means carried by a plate through .a sheet of unvulcanized rubber, placing the platecarrying'the perforating means and the perfo'rated unvulcanized rubber in a mold and vulcanzing-the}unvulcanized rubber sheet.

6. In the process of producing perforated sheet sponge rubber having its ventire surface covered with solid rubber, the steps which? comprise forcing a plurality of perforatin'gY means carried by a plate through aisheet of ,unvulcanized rubber; passing the perforatingv means carryingthe unvulcanized rubber lOt through o enings vin a mold element, the

plate forming the other mold element, and vulcanizing the rubber within the spaced mold elements.

7. In the process of producing perforated sheet sponge rubber having its entire'sun face 'covered .with solid rubber, theL'steps' which comprise placing a sheet of un'vulcan- `New York and State of New York' this 3rd day of April, 1925.

CHARLES T. DICKEY. 

